Are you tracking your team in with this? It's possible that the talent level of your players will skew the results. It's probably best to total up only the opponent and picking different opponents each time. The numbers on tackles aren't too far off and a talent difference could give those results. As for sacks and int's though something is surely off.

I'm not bothered by the comparison differences. I like the distribution %'s as you listed.
1) The tackle % have a nice distribution.
2)The sack % (esp. DL) is very good. I think if you changed your settings to have DB's blitz more-that would up the DB % of sacks.
3) The LB Int % may be a result of the TE not getting thrown to. I read somewhere else that someone noticed the TE's weren't getting any receptions. Which I would guess means they are not being thrown to. And it's the LB's that cover them?